. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. 88 THE LARVA OR NYMPH [CH. less convexly arched, though they may become rather flattened in very broad forms, especially at the sides. A definite trilobation of the abdomen is produced in the Petaliini (fig. 37) by the develop- ment of rounded or sub-triangular upwardly-projecting lobes from the sides of the terga. Extreme elongation of the last few segments is a characteristic of some Gomphine larvae (fig. 186). The sternites (b, 1-10) are rectangular plates, either flat or slightly convex. The pleura (b, pi) differ from
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. 88 THE LARVA OR NYMPH [CH. less convexly arched, though they may become rather flattened in very broad forms, especially at the sides. A definite trilobation of the abdomen is produced in the Petaliini (fig. 37) by the develop- ment of rounded or sub-triangular upwardly-projecting lobes from the sides of the terga. Extreme elongation of the last few segments is a characteristic of some Gomphine larvae (fig. 186). The sternites (b, 1-10) are rectangular plates, either flat or slightly convex. The pleura (b, pi) differ from those of the imago in being strongly chitinized. In the Anisoptera they form flat side-pieces to the. Fig. 36. Types of Anisopterid larvae, a Ictinus auslralis Selys. B. Gomphvs vulgatissimus Linn. c. Macromia sp. (Indiana, ). D. Austrocordulia refracta Tillyard. E. The same, feigning death, f. Orthetrum caledonicum Br. G. Diplacodes bipunctata Br. H. Tramea loewii Br. (Natural size.) Original. sterna; in the Zygoptera they are infolded. Eight pairs of abdominal spiracles (b, asp) are present, the eighth being the largest. Their positions, near the anterior margins of the pleura, close to the terga, correspond with those of the imago. They are, however, small and non-functional, the tracheal cords connected with them remaining solid until metamorphosis. Dorsal spines may occur on the terga of some or all of the segments, especially in running-water forms. Lateral spines. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Tillyard, Robin John, 1881-1937. Cambridge [Eng. ] : University Press
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